Chemical mechanical polishing, CMP, is commonly used in the semiconductor manufacturing industry to polish and remove metal or other materials from over a surface of a semiconductor substrate upon which semiconductor devices are being fabricated. Most commonly, conductive interconnect patterns are formed on semiconductor devices by forming a series of openings, such as vias and trenches in an insulating material disposed on a substrate surface, and then forming a conductive layer over the substrate surface and filling the openings. Damascene technology involves removing the conductive material from over the surface such that the conductive material remains only in the openings to form conductive structures such as various plugs and leads that serve as interconnection patterns and vias. CMP is also used extensively for planarizing shallow trench isolation regions.
When polishing to remove metal materials from over the substrate surface, it is critical to ensure that no metal residue remains over the surface as this can cause bridging between otherwise isolated conductive features, resulting in short circuits. Even when additional steps such as brush cleaning are used after CMP, residues remain that can still cause defects.